Re: [Tuxnes-devel] usleep() and gettimeofday() aren't portable

[Mike M. <che...@ya...>]

NTSC is 29.97 times a second or 59.94 / 2.  I don't see how waiting for a
second after drawing 30 frames will be any good to the average nintendo
buff.  Sleeping should be done with idle loops, thought we will need a
high percision clock to time them corectly.

--- Jason Dorje Short <jd...@us...> wrote:
> The usleep() function is not portable.  It's not available on win32; we 
> should use Sleep() instead.
> 
> Freeciv has code like
> 
> /***************************************************************
>    Suspend execution for the specified number of microseconds.
> ***************************************************************/
> void myusleep(unsigned long usec)
> {
> #ifdef HAVE_USLEEP
>    usleep(usec);
> #else
> #ifdef HAVE_SNOOZE		/* BeOS */
>    snooze(usec);
> #else
> #ifdef GENERATING_MAC
>    EventRecord the_event;	/* dummy - always be a null event */
>    usec /= 16666;		/* microseconds to 1/60th seconds */
>    if (usec < 1) usec = 1;
>    /* suposed to give other application processor time for the mac */
>    WaitNextEvent(0, &the_event, usec, 0L);
> #else
> #ifdef WIN32_NATIVE
>    Sleep(usec / 1000);
> #else
>    struct timeval tv;
>    tv.tv_sec=0;
>    tv.tv_usec=usec;
>    select(0, NULL, NULL, NULL, &tv);
> #endif
> #endif
> #endif
> #endif
> }
> 
> where HAVE_USLEEP, HAVE_SNOOZE, GENERATING_MAC, and WIN32_NATIVE are all
> 
> checked at configure time.
> 
> There's a similar problem with gettimeofday.  ftime is more portable and
> 
> is reported to have 10ms resolution on win32 (barely adequate for tuxnes
> 
> purposes).  So there is code like
> 
> #ifdef HAVE_GETTIMEOFDAY
>      int ret = gettimeofday(&t->start.tv, NULL);
>      if (ret == -1) {
>        report_gettimeofday_failed(t);
>        return;
>      }
> #elif defined HAVE_FTIME
>      ftime(&t->start.tp);
> #else
>      t->start.t = time(NULL);
>      if (t->start.t == (time_t) -1) {
>        report_time_failed(t);
>        return;
>      }
> #endif
> 
> I think it would be convenient to have wrappers that take times in 
> seconds, as float or double values.  Internally these can convert to 
> whatever integer form is needed by the backend.
> 
> Incidentally there is no good way to check for Sleep and other win32-api
> 
> functions because linking is done differently.  I have no idea why this 
> is but it does seem to be the case.  The solution is to check for the 
> win32 api in one go and define WIN32_NATIVE or WIN32_API or some such. 
> Then this value can be used to cover all win32-specific function calls 
> (which will be consistent across all windows platforms).
> 
> jason
> 
> 
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